British raider L'Ami Serge turned around his recent defeat by Shaneshill in France to record the biggest win of his career when he landed the Grade 1 Grande Course de Haies d'Auteuil.
Stepping up to a distance he had never tackled before, Nicky Henderson's runner was given a brilliant waiting ride by Daryl Jacob to take the prestigious prize from the wayward Alex De Larredya.
L'Ami Serge had won the Select Hurdle at Sandown on Jumps Finale Day but on numerous other occasions had not got his head in front when victory looked easier than defeat, including in the Prix la Barka last month when headed close home by Shaneshill.
Fitted with a hood to help him settle, L'Ami Serge was anchored out the back and on the inside by Jacob for much of the race but was in touch when the field lined up for the final two flights but with Alex De Larredya holding a clear advantage.
However, the leader gave away ground by jumping violently right and as he came home along the stands rail, Jacob produced L'Ami Serge from the opposite side of the course to claim the spoils for owners Simon Munir and Isaac Soude.
Henderson said: "That is one of the all-time great rides by Daryl for getting him to switch off like that.
"Here I was thinking he was a two-miler. He was second in the County Hurdle off top weight but now I know he stays we can have a very hard rethink about his entire programme."
The Willie Mullins-trained Shaneshill snatched third but last year's winner Ptit Zig and One Track Mind were unplaced.
It was the third year in a row that the race has fallen to a runner from Britain following the successes of Ptit Zig and Un Temps Pour Tout in 2015.